I failed this device last year because it was extremely old and I couldn't for the life of me get the handles to shut off.

This mother heffer is a 10" Fire back flow assembly in a vault- access is a man hole

A company called McKinstry replaced the back flow assembly for this very large commercial complex.

I tested her today!

What amazed me was how they were able to replace it. They didn't cut the road out so my guess is they had the assembly apart in pieces and built it while down in the vault, bringing piece by piece down through the hole